You might be getting a bit ahead of yourself. Some questions: You say it smokes - how much, when and what color? How much have you driven it? Have you changed the fuel filter? Have you put new diesel in?
Did you get a title? If so, what's the serial number? HMMWV's don't have VIN's. If you look at the base of the windshield frame, in front of the driver (what's called the A-beam) can you see a six digit number embossed or imprinted in the metal?
At the end of the frame rails in the rear - the curved caps that go over the ends of the rails, there should be a series of numbers - what are they?
Before you go off and start rebuilding the injector pump, you might just need to do a little fuel system maintenance. Start with basics and then if you need to spend a 1000 on a rebuild you can.
Depending on the year, it might be a 6.2NA motor (most likely) or possibly a 6.5NA. The injector pump is mechanically the same between the two, but the fuel curves are different. A 6.5 pump may have been used in conjunction with the BullyDog kit to give more fuel. How does it smoke when you use the kit? Does it run well with or without? How noisy is it? the NA trucks are pretty anemic with only 135HP and 5000# of weight.
Cheers,
Clarke